Will Fraser and Schalk Brits were the unlikely match-winning duo as both finished off sweeping attacks in style to keep Saracens on top of the Aviva Premiership table with victory over Harlequins -putting them firmly in the driving seat for a home semi-final.
Harlequins turned down the option to train at Allianz Park during the week but they may have regretted that decision after being outmuscled by an inspired Saracens side who remain unbeaten at their new home.
Both sides welcomed back their international stars but it was those in red and black that enjoyed a far better afternoon as Owen Farrell, Kelly Brown and Mako Vunipola all produced dominant displays.
Farrell gave Saracens the lead with a penalty in the fourth minute but opposite number Nick Evans responded with two of his own to give the visitors a 6-3 advantage after 13 minutes in the 30th Aviva Premiership meeting between the two sides.
But after that it was a rather one sided affair in North London as Farrell capitalised on some poor discipline at the breakdown from Harlequins, kicking three more first-half penalties and passing 400 Aviva Premiership points in the process.
Joe Marler had been sent to the bin for deliberately slowing down a Saracens attack just in front of his own try line on 17 minutes after a good burst from Chris Ashton.
And his side just couldn’t hold out in his absence as Brits grabbed the game’s first try on 26 minutes, the hooker twisting and turning well to find the try line with multiple Harlequins defenders on him.
It was Brits’ first try for two years and although Farrell failed with the conversion it gave Saracens a commanding 17-9 lead at half-time, with both fly-halfs missing a penalty just before the break.
Quins grabbed the first score of the second half as an Evans penalty drew the defending Aviva Premiership champions to within five points of their opponents.
But a fantastic attack from Saracens, started from an excellent turnover inside their own half, lead to a try for young talent Fraser who finished off a great cross-field kick from Farrell.
Ernst Joubert made a great break down the right, throwing the ball back inside as he was tackled into touch, and found Scotland captain Brown who made great ground to set up Ashton who was tackled short of the line.
The ball was then passed back to Farrell who produced an inch-perfect kick for Fraser on the left, one of three who could have scored, who collected the ball and touched down on 47 minutes.
This time Farrell was successful with the conversion to take the score to 24-12 and leave Harlequins captain Chris Robshaw, appearing in his 50th Aviva Premiership game as skipper, with a lot to ponder.
Harlequins simply had no answer to the resolute and relentless defensive display for Saracens, who are looking hot favourites for the Aviva Premiership title, and only came close to scoring at the death.
Ashton was sin binned on 73 minutes for a high tackle on replacement Maurie Fa’asavalu, his fourth yellow of the season, and Quins peppered the Saracens try line for the remainder of the game.
But the hosts stood firm with John Smit, who received a nasty cut on the head after clashing with George Robson in the tackle, epitomising the defensive resolve of the table toppers.
Farrell had earlier added a penalty on 67 minutes which was the only other score of the second half and it helped seal a seventh win in eight meetings for Saracens over Harlequins.